7x57 Load Development

[RStien321]

I have been working up handholds for my 7x57 Mauser (barrel is 1:8 twist), and found I really struggle with the 160g A Frame and 175 Partition development.

The gun shoots lights out with 143g Hammer Hunters and 139g Hornady Spire Points with near zero load development.

I’ve shot north of 100 partitions with different powders, seating depths, etc. 30 Swift A Frames (those are like gold right now) and sometimes I can get a 3 shot group in the 1.5” range, but then the same load will open up to 4” on the other side of the target. Incredibly frustrating.

Just looking for advice/suggestions if this is a common problem folks have run into? I have had a lot of luck with terminal performance of the 143 Hammer in my 28 Nosler at 500 yards on elk and mule deer, which should be similar impact velocities that the 7x57 would have at 150 yards in Africa.

 

[1r4rc]

Twist is plenty quick for the heavier bullets. Would have guessed the problem just the other way around. Throat may be set up for 140s. If you are getting good SD, play w depth... but it may be easier to just use what it likes (or take another rifle).

 

[Elkeater]

I use the 140 class hammers out of my 7-08ai (not exactly the same thing but not too far off either) and I would not hesitate to use that bullet in Africa. I’d rock the hammers and call it good. Plus it seems hammers are always available.

 

[RStien321]

I use the 140 class hammers out of my 7-08ai (not exactly the same thing but not too far off either) and I would not hesitate to use that bullet in Africa. I’d rock the hammers and call it good. Plus it seems hammers are always available.

Okay - that was my initial thought too. Just getting in my head a bit as the date of the hunt gets closer and closer.

I've had really good luck with Hammers on North America game. It's more that in my head pairing the 7x57 with a more "traditional" premium bullet was what I wanted to work. But ultimately what is more important is a super consistent, accurate, and reliable rifle. And that's what I am getting with the Hammers.

 

[AckleyHunter]

Maybe try a different powder. I tend to use slower powders with the heavier bullets. Something in the 4350 to 4831 range.

 

[RStien321]

Maybe try a different powder. I tend to use slower powders with the heavier bullets. Something in the 4350 to 4831 range.

I may revisit the 175 grain with IMR4350. I used IMR4350 with the A Frame and Hammer, but used N165 and RL19 for the 175 Partition.

 

[FlyGuy]

If the Hammer shoots well, use it.
The heavier bullets like the 4350 type powders.
Had excellent results with the 160gr AB and VV N550

 

[7x57Joe]

20 years ago, here is what I did when confronted with two 7x57s that grouped 150 grain Remington Core-Lokt bullets similar to what you are experiencing. One a Winchester M70 Featherweight, the other a M98 Mauser sporter.

A friend suggested trying 40 grains of IMR-3031. I didn't think much of the suggestion because common knowledge dictates a slower burning powder in the 7x57 case but, having tried all the slower burning powders I had, I gave it a shot.

I couldn't believe the results! One and a half inch groups consistently. Now this is from 1.25" to 4.5" groups previously.
I even tried this load (which was published in the Hornady Handbook Vol. II) with bullets from 130 to 175 grain and all were consistent with velocities running 2800 fps to 2500 fps. Speed on the cantankerous 150's was 2392 fps, not fast but, consistent accuracy.

If you are shooting a modern rifle, you may want to consider this.

The last buck I killed with the 7x57 was with this load.

 

[dchamp]

Why not try the 160 Hammer or even one of their heavier bullets for the 7mm. Hammer are good bullets. Other options you might consider are the North Fork 175gr or the 156gr Norma Oryx. North Fork has theirs in stock and Raven Rock Precision has the 156gr Oryx in stock at a very good price. Both the North Fork and Norma Oryx are excellent bullets. In my mind it is the shooting range and class of animals you plan to encounter that dictates the bullet you choose.

 

[Rare Breed]

I have been working up handholds for my 7x57 Mauser (barrel is 1:8 twist), and found I really struggle with the 160g A Frame and 175 Partition development.

The gun shoots lights out with 143g Hammer Hunters and 139g Hornady Spire Points with near zero load development.

I’ve shot north of 100 partitions with different powders, seating depths, etc. 30 Swift A Frames (those are like gold right now) and sometimes I can get a 3 shot group in the 1.5” range, but then the same load will open up to 4” on the other side of the target. Incredibly frustrating.

Just looking for advice/suggestions if this is a common problem folks have run into? I have had a lot of luck with terminal performance of the 143 Hammer in my 28 Nosler at 500 yards on elk and mule deer, which should be similar impact velocities that the 7x57 would have at 150 yards in Africa.

Interesting. I had my 275 Rigby opened up so it easily shoots 175 grain bullets which as you know we are talking about the same caliber. Yet my 140 grain bullets give clover leaf groups at 100 yards while I am still searching for the same groupings in 175 grain